Science to look forward to

BepiColombo will be the first mission to study Mercury with two spacecraft at the same time. MPO will orbit close to the planet’s surface, and Mio in a larger elliptical orbit.

So far, MPO and Mio – the latter nestled inside a protective sunshield – have been stacked on top of their ‘trusty engine’ MTM. Several of the mission’s scientific instruments can’t yet be used, or are partially hindered, until the stacked spacecraft separate after arriving at Mercury in November 2026.

Once ‘unstacked’, MPO and Mio can finally use all their instruments to their full potential.

For example, instead of the modest black-and-white images taken by MTM’s monitoring cameras, MPO will scan Mercury’s surface in high resolution in X-rays (with imaging spectrometer MIXS), visible and near-infrared light (with stereo camera and spectrometer SIMBIO-SYS) and infrared light (with imaging spectrometer MERTIS). To ensure that we accurately capture Mercury’s topography, MPO’s BELA laser altimeter instrument will measure the precise height and shape of Mercury’s surface.

Put together, this data will give us a precise map of Mercury’s surface, and tell us what it’s made of, how it formed, how it changes over time, and what temperature it is. Flying over Mercury’s poles, MPO will also be able to peer into craters filled with permanent shadow – if there is water on Mercury, this is where it would be!

And, while both Mio and MPO have already used their magnetometers and some of their particle detectors to investigate Mercury’s surroundings, their measurements will be more sensitive and precise when the spacecraft are separated. After separation, Mio will additionally be able to use its sodium imager MSASI and dust detector MDM to investigate other material near Mercury.